Egg, zygote, 2cell-stage, 4 cell-stage, morula, blasocyst
Answer:
1). Prophase: This known to be the first step of mitosis. This phase is denoted when genetic fibres within the cell nucleus known to be chromatin begins to condense and become tightly compacted together.
2). Metaphase: This is known to be the second stage that follows prophase and prometaphase and progrsses to anaphase. Metaphase starts to occur when once all the kinetochore microtubules get attached to the sister chromatid which is brought about by the force generated.
3). Anaphase: At this phase, the centomeres at the centre of the sister chromatids are severed. It ensures that each chromosome receives identical copies of the parent cell’s DNA.
4). Telophase: This is the last phase of mitosis. It occurs when the newly formed daughter chromosomes get their own individual nuclear membranes and identical sets of chromosomes.
The main purpose of mitosis is to accomplish cell regeneration, cell replacement, and growth in living organisms.
With the advent of industrialization, several trees have been cut at an alarming rate for raw materials and various other purposes. This felling of trees can be regulated by selective cutting, clear-cutting and shelterwood cutting.
Forest fires are one of the common causes of loss of forests. Sometimes the forest land is set on fire to make the land available for commercial purposes. Once cleared, there can be no vegetation. Natural forest fires are also responsible for the destruction of huge forest covers. Latest fire fighting techniques should be adopted to conserve the forest. However, forest fires are an important part of the ecosystem and it helps replenish nutrients in the soil from dead and decaying matter.
More trees should be planted to increase the forest cover. Trees should be selected according to the geographical conditions of a particular region and proper care should be taken during the growth of trees.
Prevention of exploitation of forestry and forest products is necessary for the conservation of forest.
The existing forests should be protected from diseases by spraying chemicals, antibiotics or development of pest-resistant strains of trees.
12. they weight about 45 pounds or more
13 am not sure sorry
Option (A) identifies them correctly.
During Meosis 2 daughter cells are formed from a single cell and the chromosomes are equally divided in both the cells.
So, Cell P had 60 chromosome, after miosis 2 daughter cells of each having 30 chromosomes formed, and again after Miosis of from each of those 2 those daughter cells, 2 more daughter cells are formed with equal naumber of chtomosome which equals 15.